1. Field of Invention
The present invention relates to information delivery services, and in particular to improving the likelihood of program reception and playback in a local storage and playback broadcast system.
2. Related Art
In many audio playback systems the selected audio programs are provided on a physical medium, such as compact disk (CD), analog tape (e.g., cassette), or removable semiconductor memory (e.g., SmartMedia(copyright) card manufactured by Toshiba Corporation, Memory Stick(copyright) by Sony Corporation, or CompactFlash(copyright) by Sandisk Corporation). The likelihood of successful program playback is high as long as the storage medium is undamaged. Alternatively, in certain types of information delivery systems audio programs are broadcast for live playback using media such as commercial amplitude and frequency modulated (AM, FM) radio or television signals. The likelihood of high quality playback using broadcast signals is proportional to the quality of signal reception. The greater the distance between transmitter and receiver, for example, the lower the likelihood of acceptable playback quality. For instance, in a typical commercial radio live (direct) broadcast system users (listeners) are likely to tune to another broadcast station when subjective playback quality becomes unacceptable.
Another communications system alternative is to broadcast audio programs to a mobile receiver for local storage (e.g., in the receiver) and subsequent playback. But program information broadcast over an unreliable (e.g., noisy) wireless broadcast medium is subject to loss of quality during transmission. What is desired in such a system are methods and measures that will improve the likelihood that the broadcast program will be properly received, reassembled, stored, and played back.
In a local storage and playback broadcast system, a program (e.g., compressed audio program) is subdivided for playback into at least one segment that is a logically cohesive information group. Each program (including segments) is also divided for broadcast into fixed length data units (packets).
Processing parameters are defined to aid each receiver""s storage (e.g., capture, reassembly, memory management) and playback of the program. The processing parameters are related to the program as a whole (e.g., program identifier, content compression type), each segment in the program (e.g., segment sequence number), or each packet in the program (e.g., packet sequence number).
The broadcast signal is structured in a series of frames. Each frame includes a header and at least one of the program""s packets. In some embodiments, one copy of one or more of the processing parameters is included in the frame header for each program packet in the frame, thereby ensuring that each receiver has a high probability of receiving each parameter. In some embodiments one copy of one or more of the parameters is included in a segment header for each program segment.